/*
 * CompressionServletResponseWrapper.java
 * $Header: /home/cvsroot/cvs/Reporter/JavaSource/jaoso/framework/web/filter/compression/CompressionServletResponseWrapper.java,v 1.1 2006/02/15 10:23:31 zhangqi Exp $
 * $Revision: 1.1 $
 * $Date: 2006/02/15 10:23:31 $
 *
 * ====================================================================
 *
 * The Apache Software License, Version 1.1
 *
 * Copyright (c) 1999 The Apache Software Foundation.  All rights
 * reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The end-user documentation included with the redistribution, if
 *    any, must include the following acknowlegement:
 *       "This product includes software developed by the
 *        Apache Software Foundation (http://www.apache.org/)."
 *    Alternately, this acknowlegement may appear in the software itself,
 *    if and wherever such third-party acknowlegements normally appear.
 *
 * 4. The names "The Jakarta Project", "Tomcat", and "Apache Software
 *    Foundation" must not be used to endorse or promote products derived
 *    from this software without prior written permission. For written
 *    permission, please contact apache@apache.org.
 *
 * 5. Products derived from this software may not be called "Apache"
 *    nor may "Apache" appear in their names without prior written
 *    permission of the Apache Group.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 *
 * [Additional notices, if required by prior licensing conditions]
 *
 */
package jaoso.framework.web.filter.compression;

import java.io.IOException;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;

import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpServletResponseWrapper;

/**
 * Implementation of <b>HttpServletResponseWrapper </b> that works with the
 * CompressionServletResponseStream implementation..
 * 
 * @author Amy Roh
 * @author Dmitri Valdin
 * @version $Revision: 1.1 $, $Date: 2006/02/15 10:23:31 $
 */
public class CompressionServletResponseWrapper extends
        HttpServletResponseWrapper
{
    /**
     * Descriptive information about this Response implementation.
     */
    protected static final String info = "CompressionServletResponseWrapper";

    // ----------------------------------------------------- Instance Variables

    /**
     * Original response
     */
    protected HttpServletResponse origResponse = null;

    /**
     * The PrintWriter that has been returned by <code>getWriter()</code>, if
     * any.
     */
    protected PrintWriter writer = null;

    /**
     * The ServletOutputStream that has been returned by
     * <code>getOutputStream()</code>, if any.
     */
    protected ServletOutputStream stream = null;

    /**
     * Content type
     */
    protected String contentType = null;

    /**
     * The threshold number to compress
     */
    protected int threshold = 0;

    /**
     * Debug level
     */
    private int debug = 0;

    // ----------------------------------------------------- Constructor

    /**
     * Calls the parent constructor which creates a ServletResponse adaptor
     * wrapping the given response object.
     */
    public CompressionServletResponseWrapper(HttpServletResponse response)
    {
        super(response);
        origResponse = response;

        if (debug > 1)
        {
            System.out
                    .println("CompressionServletResponseWrapper constructor gets called");
        }
    }

    /**
     * Set threshold number
     */
    public void setCompressionThreshold(int threshold)
    {
        if (debug > 1)
        {
            System.out.println("setCompressionThreshold to " + threshold);
        }

        this.threshold = threshold;
    }

    /**
     * DOCUMENT ME!
     * 
     * @param length
     *            DOCUMENT ME!
     */
    public void setContentLength(int length)
    {
    }

    // --------------------------------------------------------- Public Methods

    /**
     * Set content type
     */
    public void setContentType(String contentType)
    {
        if (debug > 1)
        {
            System.out.println("setContentType to " + contentType);
        }

        this.contentType = contentType;
        origResponse.setContentType(contentType);
    }

    /**
     * Set debug level
     */
    public void setDebugLevel(int debug)
    {
        this.debug = debug;
    }

    /**
     * Return the servlet output stream associated with this Response.
     * 
     * @exception IllegalStateException
     *                if <code>getWriter</code> has already been called for
     *                this response
     * @exception IOException
     *                if an input/output error occurs
     */
    public ServletOutputStream getOutputStream() throws IOException
    {
        if (writer != null)
        {
            throw new IllegalStateException(
                    "getWriter() has already been called for this response");
        }

        if (stream == null)
        {
            stream = createOutputStream();
        }

        if (debug > 1)
        {
            System.out.println("stream is set to " + stream
                    + " in getOutputStream");
        }

        return (stream);
    }

    /**
     * Return the writer associated with this Response.
     * 
     * @exception IllegalStateException
     *                if <code>getOutputStream</code> has already been called
     *                for this response
     * @exception IOException
     *                if an input/output error occurs
     */
    public PrintWriter getWriter() throws IOException
    {
        if (writer != null)
        {
            return (writer);
        }

        if (stream != null)
        {
            throw new IllegalStateException(
                    "getOutputStream() has already been called for this response");
        }

        stream = createOutputStream();

        if (debug > 1)
        {
            System.out.println("stream is set to " + stream + " in getWriter");
        }

        //String charset = getCharsetFromContentType(contentType);
        String charEnc = origResponse.getCharacterEncoding();

        if (debug > 1)
        {
            System.out.println("character encoding is " + charEnc);
        }

        // HttpServletResponse.getCharacterEncoding() shouldn't return null
        // according the spec, so feel free to remove that "if"
        if (charEnc != null)
        {
            writer = new PrintWriter(new OutputStreamWriter(stream, charEnc));
        } else
        {
            writer = new PrintWriter(stream);
        }

        return (writer);
    }

    /**
     * Create and return a ServletOutputStream to write the content associated
     * with this Response.
     * 
     * @exception IOException
     *                if an input/output error occurs
     */
    public ServletOutputStream createOutputStream() throws IOException
    {
        if (debug > 1)
        {
            System.out.println("createOutputStream gets called");
        }

        CompressionResponseStream stream = new CompressionResponseStream(
                origResponse);
        stream.setDebugLevel(debug);
        stream.setBuffer(threshold);

        return stream;
    }

    /**
     * Finish a response.
     */
    public void finishResponse()
    {
        try
        {
            if (writer != null)
            {
                writer.close();
            } else
            {
                if (stream != null)
                {
                    stream.close();
                }
            }
        } catch (IOException e)
        {
        }
    }

    // ------------------------------------------------ ServletResponse Methods

    /**
     * Flush the buffer and commit this response.
     * 
     * @exception IOException
     *                if an input/output error occurs
     */
    public void flushBuffer() throws IOException
    {
        if (debug > 1)
        {
            System.out
                    .println("flush buffer @ CompressionServletResponseWrapper");
        }

        ((CompressionResponseStream) stream).flush();
    }

    /**
     * Returns character from content type. This method was taken from tomcat.
     * 
     * @author rajo
     */
    private static String getCharsetFromContentType(String type)
    {
        if (type == null)
        {
            return null;
        }

        int semi = type.indexOf(";");

        if (semi == -1)
        {
            return null;
        }

        String afterSemi = type.substring(semi + 1);
        int charsetLocation = afterSemi.indexOf("charset=");

        if (charsetLocation == -1)
        {
            return null;
        } else
        {
            String afterCharset = afterSemi.substring(charsetLocation + 8);
            String encoding = afterCharset.trim();

            return encoding;
        }
    }
}